O-Chem pi and sigma bonds questions?

[kthakore]

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Basically I came across some text that said the following organic chemical had 24 sigma and 7 pi bonds.

I get 20 sigma bonds here is how:

7 from each pi bond
+ 5 from H bonds in the ring
+ 3 C-C Single Bonds in the ring
+ 4 Single bonds in the attached alkene
+ 1 C-H bond at the end there
= 20 not 24.

Where am I going wrong? Also how do u name this chemical. Do we name something this complex on the mcat?

 

[loveoforganic]

Pi bonds have a sigma bond component too.

The name is (2E,4E)-6-oxo-6-phenylhexa-2,4-dienal.

God no you would never have to name anything like that.

 

[phEight]

I get 20 sigma bonds here is how:

7 from each pi bond
+ 5 from H bonds in the ring
+ 3 C-C Single Bonds in the ring
+ 4 Single bonds in the attached alkene
+ 1 C-H bond at the end there
= 20 not 24.

Where am I going wrong?

I'm counting 24 sigma bonds. It seems you're not counting the sigma bonds that are in the double bonds. A double bond consists of one sigma and one pi bond. A triple bond consists of one sigma and two pi bonds.

 

[hopslam]

phEight is right on track

 

[sv3]

if we had to name something like that there would be one less computer in the room and I'd need bail money

 

[kthakore]

oops thx. I get it now. Also phew on naming this monster.

 

[kthakore]

Indeed sv3. Also they would need a clean up of ammonia in my aisle.